package codeforces25;

import java.util.Scanner;

/**
 * Codeforces 25. Problem B
 * 
 * @author Aleksandr Nikiforov
 */
public class ProblemB {

	public static void main(String[] args) {
		ProblemB problem = new ProblemB();
		problem.solve();
	}

	private void solve() {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		String s = sc.next();
		for (int i = 0; i < n; i+=2) {
			String part;
			boolean end = false;
			if (i + 3 == n || i + 2 == n) {
				part = s.substring(i, n);
				end = true;
			} else {
				part = s.substring(i, i + 2);
			}
			System.out.print(part);
			if (!end) {
				System.out.print("-");
			} else {
				break;
			}
		}
		System.out.println();
	}

}
